Hello guys,

I'm having problems with entering an answer on my current homework problem. My course is online and it's asking me

For what values of the common ratior is it possible to find the sum of an infinite geometric series? (Enter your answer using interval notation.)?I tried using (-1,1) because |r| < 1 , but it appears as a wrong answer I'm a wrong here?

r could be between -1 and 1